Electroluminescent devices and displays with integrally fabricated address and logic devices fabricated by printing or weaving

ABSTRACT

Improved electroluminescent and photonic devices with integrated logic and control circuits are disclosed. Low mobility, contact barrier, space charge limitation and carrier balancing are provided solutions that increase efficiency, reliability and longevity of the devices. Device power loss and power requirements are reduced. True-ohmic contact materials allow a gate-controlled, light emitting organic triode MESFET configuration that eliminates commonly used ITO thereby increasing luminous output, and providing ease of address and control by integrally fabricated complementary MESFET address and control circuitry. The devices can be fabricated by printing or by weaving appropriate materials, and can be configured as color displays.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/218,233, filed Dec. 22, 1998. The aforementionedrelated patent application is herein incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention is directed toward triode electroluminescentdevices, structures and materials comprising carrier injection contactswhich are applied to improve or replace organic light emitting diode(LED) fabrication processes and contact materials. More particularly,the invention is directed toward solution deposited and ink-jet printedmetal-organic and organic-polymer semiconductors and electroluminescentsemiconductors which are used to form panel displays and other photonicdevices and products. Alternately, the devices can be fabricated byweaving constituent materials.

[0004] 2. Description of the Related Art

[0005] U.S. Pat. Nos. 5,656,883 and 5,663,559, both to Alton O.Christensen, Sr. (Christensen) disclose true-ohmic contact structuresfor injecting charge into a vacuum interface, namely, field emission.U.S. Pat. No. 5,977,718, U.S. patent application Ser. No. 08/281,912 andU.S. patent application Ser. No. 09/218,233, all to Christensen,disclose other materials of a true-ohmic contact interface to inorganic,organic and polymer devices. More specifically, U.S. patent applicationSer. No. 09/218,233 discloses woven polymer semiconductors andelectroluminescent fibers comprising pixel components and controlcircuitry. Furthermore, U.S. patent application Ser. No. 08/281,912discloses true-ohmic contacts to inorganic and metal-organic materials.

[0006] The status of the prior art in electroluminescent (EL) polymerdevice design is well documented by the review article by R. H. Friend,et al., in “Electroluminescence in Conjugated Polymers,” NATURE,Vol.397, Jan. 14, 1999, p121. This article, hereafter referred to as“Friend”, is limited to conjugate polymer light emitting diode devices(LED's) having indium-tin oxide (ITO) as the hole-injecting contact. Thereference is cited not only as background of the prior art, but alsobecause specific needs for improvement in the prior art are discussed.These are summarized as follows by topic with applicable page, columnand initial line number:

[0007] 1. Low barrier contacts: (page 124, col. 2, line 17) Friendstates that both hole-injecting and electron-injecting electrodes withrelatively low barriers for charge injections are required so that highcurrent densities and concomitant light emission are produced at lowvoltages.

[0008] 2. Low mobility: (page 124, col. 2, line 12) Friend states thatmobility is field (energy) dependent.

[0009] 3. Space charge limitation: (page 124, col. 2, line 1) Friendstates that current flow in LED's is not limited by injection, but bulklimited by build up of space charge from low carrier mobility,.

[0010] 4. Current balancing: (page 125, col. 1, line 5) Friend statesthat injection and transport of holes into the bulk of the polymer mustbe matched by injection and transport of electrons from the oppositeelectrode, and that the control of injection rates (by introducinghetrojunctions) has been shown to be effective for obtaining chargebalance.

[0011] 5. Reduced radiative emission: (page 126, col. 1, line 25) Friendstates that in device structures of the type discussed here, thepresence of a metallic cathode (ITO) provides a mirror thereby reducingthe emission rates.

[0012] 6. Interchain interaction reduces radiative emission: (page 125,col. 2, line 38 and page 126, col. 1, line 3) Friend states thatinterchain interactions produce lower energy excited states not stronglyradiative,

[0013] 7. Need economic integrated pixel control circuitry; (Page 127,col. 1) Friend discusses needs for economically efficient means forproducing integrated pixel control circuitry.

[0014] Improvements in these areas will be set forth in subsequentsections of this disclosure.

SUMMARY OF THE INVENTION

[0015] This disclosure is directed toward improvements in efficiency andoperation of solution deposited and ink-jet printed electroluminescentand photonic devices. These devices can also be fabricated by weaving.Prior art interface low mobility, contact barrier, space chargelimitation and carrier balancing are incorporated. These properties tendto increase efficiency, increase reliability and longevity, reduce apower loss, and reduce power requirement of LED devices. Contactmaterials and a light emitting triode configuration are disclosed thateliminates ITO commonly used in prior art devices. This increasesluminous output, and provides ease of address and control by the use ofintegrally fabricated triode address and control circuitry.

[0016] As mentioned above, U.S. Pat. Nos. 4,663,559, and 5,656,883 toChristensen disclose a true-ohmic, no-barrier, non-tunneling, injectingcontact between the low work function metal Cr₃Si and SiO₂ (silica) as an-type semiconductor, co-deposited as a cermet. Contact equilibriumaccumulates the silica conduction band with electrons. These electronsare less than 1 electron volt (eV), and typically 0.6 eV from vacuumlevel. In U.S. patent application Ser. No. 09/218,233, this sameinterface physics is extended to an injecting, non-tunneling ohmiccontact obtained between the cermet and n-type polymer semiconductorsand electroluminescent (EL) material. This type of contact, atequilibrium, injects electrons into the polymer semiconductor conductionband, prohibits tunneling, and permits only minimal hole conduction. Theohmic contact to EL semiconducting polymers allows a third, gateterminal to be effective in controlling avalanche in the semiconductor.The cermet contact to EL polymer blocks hole current flow, increases ELcarrier recombination, and improves efficiency and luminous output overprior art tunneling EL devices. Furthermore, U.S. patent applicationSer. No. 09/218,233 discloses woven polymer semiconductors andelectroluminescent fibers comprising pixel components and controlcircuitry. The apparatus and methods can be used to produce a flexible,cloth-like flat screen display.

[0017] U.S. Pat. Nos. 5,656,883 and 5,663,559, U.S. patent applicationSer. No. 08/281,912 and U.S. patent application Ser. No. 09/218,233 arehereby entered into this disclosure by reference. This disclosure setsforth apparatus and methods for improving triode electroluminescentdevices, structures and materials comprising carrier injection contacts,which are now applied to improve or replace organic LED fabricationprocesses and contact materials.

[0018] The improved apparatus and methods are particularly applicable tosolution deposited and ink-jet printed metal-organic and organic/polymersemiconductors and electroluminescent semiconductors that form devices,displays and other photonic devices and products. Elements are printedin pattern and in a sequence required to produce cooperative elements ofthe devices.

[0019] An alternate means of fabrication is the weaving processdisclosed in U.S. patent application Ser. No. 09/218,233 and previouslyentered into this disclosure by reference. A class of such polymers,consisting of microfibers of micron and sub-micron dimension, is woveninto silk-like fabrics. The ability of certain co-polymers to emit lighthas been known for less than two decades. Selected conjugate orladder-type polymers may have dielectric, resistive, thermalconductivity, n or p type conductivity and EL properties.

[0020] The above references entered by reference teach the principles,materials and means for providing true solid/solid interfaceMott-Gurney, no-barrier, true-ohmic contact to n-type semiconductinginorganic and metal-organic compounds, polymers and co-polymers of bandgaps greater than 2 eV used in electronic circuitry, EL and otherphotonic devices. In summary, the teachings and effects are as follows:

[0021] 1. When contact is made between an n-type semiconductor and aconductor whose work function □_(m) is less than half of (E_(g)/2□)where E_(g) is the semiconductor band gap and □ is the electronaffinity, then charge exchange occurs to obtain equilibrium;

[0022] 2. in the charge exchange, interface traps are filled and theconduction band of the semiconductor is accumulated with electrons;

[0023] 3. the greater the positive difference between (E_(g)/2−□−□_(m))and work function □_(m) the greater charge exchange occurs to achieveequilibrium, filling some bulk traps as well; and

[0024] 4. the net effect is to increase conductivity, electron mobilityand reduce space charge.

[0025] These principles, materials, and methods are utilized in thepresent invention. Two high conductivity contacting metals, each capableof producing true ohmic contact to semiconductors and EL semiconductorsof band gap greater than 1.5 eV, are employed in the apparatus of thepresent invention. These contact materials are CuCa₂ with a workfunction of about 1.6 eV, and Al₂Li₃ with a work function of about 1 eV.CuCa₂ prevents diffusion and electromigration of Cu, has a relativelyhigh conductivity and adapts readily into the prior art LED processingenvironment requiring background pressure of 10⁻⁶ mbar of O₂ (seeFriend, page 123, col. 2, line 34). When fabricated by printing or otherdeposition means, Al₂Li₃ requires a suitably positive pressure of argon(Ar) both during the solution formation and the deposition. Polymers andco-polymers of electroluminescent devices and both CuCa₂ and Al₂Li₃require protective coating, or overall encapsulation, to preventoxidation. Either CuCa₂ contacts or preferably Al₂Li₃ contacts improveLED operation. Both CuCa₂ and Al₂Li₃ alloy with polymer and co-polymersemiconductors and electroluminescent devices at about 30° centigrade.

[0026] Disclosed are method and means of eliminating the barrier andreduced radiative emission of prior art ITO cathode by transforming theLED structure into a triode gate controlled metal semiconductor fieldeffect transistor (MESFET)-like structure having a surrounding gate thatcontrols carrier energy and carrier balance. The true-ohmic contactsdisclosed inject carriers and fill interface and bulk traps. Thisincreases carrier mobility by a factor approaching 10 ⁴ and space-chargedistance by a significant factor, allowing more concentration ofradiative chain emission and thus more radiated output. The pixel MESFEToperates in a short-channel, normally “off”, gate-controlled high-energymode, up to and including avalanche, thereby increasing radiative outputand decreasing power required. Basis information on MESFET operation isincluded in the literature. The MESFET field has polymer-chain fieldorientation, rather than LED cross-chain field, thereby furtherimproving efficiency and radiative emission by lowering non-radiativeinterchain reaction. The MESFET's surrounding gate enhances carrierbalancing. Carrier balancing may be “tuned” for a particular polymer orcopolymer by the positioning of the gate relative to the cathode. TheMESFET gate electrode provides reduced cross talk and ease of pixeladdressing as compared to LED's.

[0027] Since the MESFET device comprises organic elements, it willsometimes be referred to as an “organic” MESFET or “OMESFET”.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] So that the manner in which the above recited features,advantages and objects the present invention are obtained and can beunderstood in detail, more particular description of the invention,briefly summarized above, may be had by reference to the embodimentsthereof which are illustrated in the appended drawings:

[0029]FIG. 1 is a partial cross section of a prior artelectroluminescent diode;

[0030]FIG. 2 is a partial cross section of an improve version of theprior art diode shown in FIG. 1;

[0031]FIG. 3 is a cross section schematic of the preferred OMESFET usedin pixels and control circuitry;

[0032]FIG. 4 is a partial planar view schematic of the preferred OMESFETused in pixels and control circuitry shown in FIG. 3;

[0033]FIG. 5 is a partial cross section of an OMESFET suitable forfabrication using printing methods;

[0034]FIG. 6 is a partial planar view of the OMESFET illustrated in FIG.5;

[0035]FIG. 7 is a planar topology of a pixel comprised of three pairs ofred, green and blue (RGB) emitting OMESFET's;

[0036]FIG. 8 is a cross section of the preferred complementary OMESFETlogic device;

[0037]FIG. 9 is a conceptual, planar diagram of an ink-jet printingsystem filling polymer semiconductor areas in pattern and sequence toform an EL device; and

[0038]FIG. 10 is a partial cross section showing interconnected pixelelements shown in FIG. 3 and the OMESFET logic device shown in FIG. 8.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT

[0039] The invention discloses electroluminescent and photonic deviceswith improved efficiency and operation. The devices are designed forefficient and cost effective fabrication using solution deposition andink-jet printing methodology. Alternately the devices can be woven fromappropriate materials as disclosed in U.S. patent application Ser. No.09/218,233.

[0040] Interface low mobility, contact barrier, space charge limitationand carrier balancing are incorporated in the improved devices. Theseproperties tend to increase efficiency, increase reliability andlongevity, reduce a power loss, and reduce power requirement of LEDdevices. The use of true-ohmic contact materials in a light emittingtriode OMESFET configuration is disclosed. This contact material in thedisclosed configuration eliminates ITO commonly used in prior artdevices.

[0041] This increases luminous output, and provides ease of address andcontrol by the use of integrally fabricated triode address and controlcircuitry.

[0042] The above cited references, which are entered into thisdisclosure by reference, teach the principles, materials and means forproviding true solid/solid interface Mott-Gurney, no barrier, true-ohmiccontact to n-type semiconducting inorganic and metal-organic compounds,polymers and copolymers of band gaps greater than 2 eV. These contactsare embodied in electronic circuitry, EL and other photonic devices.Again summarizing, the references teach that a contact made between ann-type semiconductor and a conductor whose work function is less thanthe semiconductor band gap, charge exchange occurs to obtain a state ofequilibrium. In the charge exchange process, interface traps are filledand the conduction band of the semiconductor is accumulated withelectrons. The greater the difference between the band gap and the workfunction, the greater the exchange to achieve equilibrium therebyfilling some bulk traps as well. The net effect is to increaseconductivity and electron mobility of the device. These basic principlesare applied to the present disclosure.

[0043] Two high conductivity contacting metals, each capable ofproducing true ohmic contact to semiconductors and EL semiconductors ofband gap greater than 2 eV, are employed in the present invention. Thesecontact materials are CuCa₂ with a work function of about 1.6 eV, andAl₂Li₃ with a work function of about 1 eV. CuCa₂ adapts readily into theprior art LED processing environment requiring background pressure of10⁻⁶ mbar of O₂. As mentioned previously, printing and other solutiondeposition processes of Al₂Li₃ requires a suitably positive pressure ofargon (Ar) both during the solution formation and the deposition.Polymers and co-polymers of electroluminescent devices and both CuCa₂and Al₂Li₃ require protective coating, or overall encapsulation, toprevent oxidation. Either CuCa₂ contacts, or preferably Al₂Li₃, contactsimprove LED operation. SiO₂ pacifies Al₂Li₃.

[0044] Prior art LEDs are contact barrier controlled and operate bytunneling of carriers. In the present invention, barriers are eliminatedand radiative emission is reduced relative to prior art ITO cathodedevices by transforming a LED structure into a triode having structuralcharacteristics of an OMESFET including a surrounding Schottky gate thatcontrols carrier energy and balance. True-ohmic contacts are formed andinject carriers fill interface and bulk traps. This increases carriermobility by a factor approaching 10⁴ and space-charge distance by afactor of 40 or more, thereby allowing more concentration of radiativechain emission and thus more radiated output.

[0045] The pixel OMESFET embodiment operates in a short-channel,normally “off”, gate-controlled high-energy mode, up to and includingavalanche, thereby increasing radiative output and decreasing powerrequired. Details of MESFET operation is included in standard texts suchas a publication by M. E. Sze, Physics of Semiconductor Devices, page322. The OMESFET field has polymer-chain field orientation, rather thanLED cross-chain field, thereby further improving efficiency andradiative emission by lowering non-radiative interchain reaction. TheOMESFET's surrounding gate enhances carrier balancing.

[0046] An important feature of the invention is that carrier balancingmay be “tuned” for a particular polymer or co-polymer by the positioningof the gate relative to the cathode. The OMESFET gate electrode providesreduced cross talk and ease of pixel addressing as compared to LED's.OMESFET pixel address and control circuitry are integrally fabricatedwith pixel arrays for efficiency and economy of fabricating displayproducts.

DESCRIPTION OF THE DEVICES

[0047] Attention is first directed to FIG. 1 which is a partial sectionview of the prior art LED. The structure is generally denoted by thenumeral 10. Starting at the bottom of the illustration, an organic ELmaterial 14 contacts an ITO hole injection barrier contact 12. A lowelectron barrier contact is identified at 15 and may be Al, Ca, Mg orcombinations thereof as reviewed by Friend. The resulting barrier isabout 0.2 eV. Components 14 and 15 are encapsulated with a polymerencapsulating material 16. The prior art device is illustrated forbackground purposes only, and no claims are made regarding thisillustration of the prior art.

[0048]FIG. 2 illustrates a partial section of an improved LED. Thestructure is generally denoted by the numeral 20. The device 20 is animprovement over the prior art device in function as well as infabrication. Regarding fabrication, the device 20 as embodied can besolution deposited or “printed”, as opposed to prior art deposition andetching methods. These techniques significantly reduce fabricationcosts. As an example, an improvement is embodied by first printing orotherwise depositing organic electroluminescent material 14 upon acontact 12, followed by an overlay printing of a true-ohmic contactmetal 18, and finally by an overlay printing of an interconnect metal17. The true-ohmic contact metal 18 preferred is one having the largestratio of the band gap of the EL material 14 to the work function of thecontact metal. The preferred contact 18 is Al₂Li₃ of work function ofabout 1 eV. Solution forming and printing volatile Al₂Li₃ requires thesame oxygen free environment as for layer 14, plus a suitable positivepressure of Ar. An alternative embodiment for contact 18 is to printCuCa₂ of work function of about 1.6 eV, which does not require an Arenvironment. Both contact metals result in the previously discussesdevice operation and performance specifications. The same oxygen freeenvironment required for printing of the EL material 14 is used to formsolution and printing of CuCa₂. Components 14, 17 and 18 areencapsulated with a polymer material 16 on the contact 12, which ispreferably a ITO hole injection contact 12.

[0049] Attention is next directed to FIG. 3 which is a partial sectionof the improved EL device embodied as a OMESFET structure used in red,blue and green (R, B and G) pixels, and also used in pixel address andcontrol circuitry. The OMESFET is an integral component of a videodisplay, which is discussed in subsequent sections of this disclosure.The OMESFET structure is generally denoted by the numeral 30. The device30 comprises a metal-organic or copolymer n-type EL semiconductor 33. Asource true-ohmic contact metal 32 contacts the source end of the ELsemiconductor 33, and a drain true-ohmic contact metal 37 contacts thedrain end of the EL semiconductor 33. A high work function surroundinggate metal 35 contacts the EL semiconductor 33 between the sourcecontact metal 32 and the drain contact metal 37. The gate 35 ispreferably fabricated from printed Au or other conductors and having abarrier to n-type semiconductor 33 of 5 eV or more. Interconnect metalsfor source 31, drain 37 and gate 35 are denoted by 31, 36 and 34,respectively. When the gate 35 is located equidistant from source 32 anddrain 37, the distances designated 38 and 39 are equal and about 3000nanometers (nm) each. Some co-polymer semiconductors may require gate 35to be closer to source contact 32 for current balancing. In thatinstance, neither 38 nor 39 should exceed 3000 nm, to eliminatespace-charge current limitation. Current balancing can thereby be“tuned” by placement of the gate 35.

[0050] Still referring to FIG. 3, the OMESFET device 30 is operatednormally in the “off” mode. The source interconnect metal 31 is normallyconnected to system ground potential, as shown at 71 in FIG. 7. Gateinterconnect metal 34 is operated at a negative potential relative tothe source 31. That potential is supplied by address and control logicas discussed in subsequent sections of this disclosure. The draininterconnecting metal 36 is operated at a positive potential relative tothat of source 31 and gate interconnect 34. That potential is alsosupplied by address and control logic device illustrated in FIG. 10.

[0051] Attention is next directed to FIG. 4, which is a partial planarview of the OMESFET shown in sectional view in FIG. 3. The structure isagain denoted by the numeral 30. The organic semiconductor 33 is shownbounded on the left with the true-ohmic contact metal 32 of the source,and on the right by the true-ohmic contact metal 37 of the drain. Thehigh barrier surround gate conductor 35 is shown positioned on theorganic semiconductor 33 approximately midway between the true-ohmiccontact metals 32 and 37. The interconnect metals 33, 34 and 36 havebeen omitted for clarity.

[0052]FIG. 5 shows a partial cross section of the EL device configuredas an OMESFET and further configured for fabrication using solutiondeposition and printing techniques. This embodiment of the improvedOMESFET is denoted as a whole by the numeral 50. Organic semiconductormaterial is deposited upon a substrate 51. True-ohmic contact metals 53and 55 are next deposited upon the organic semiconductor material 33 aselements source and drain contacts, respectively. Preferably in the samefabrication step, a high barrier surface gate conductor 54 is depositedupon the organic semiconductor 33 at a distance 38 from the true-ohmiccontact metal 53 and a distance 39 from the true-ohmic contact metal 56.Finally, source interconnect metal 52, drain interconnect metal 55, andgate interconnect metal 34 are deposited over the elements 53, 56 and54, respectfully. The elements must be encapsulated to protect fromoxygen. This encapsulation is not shown for reasons of clarity.

[0053]FIG. 6 is a partial planar view of the OMESFET shown in sectionalview in FIG. 5. The structure is again denoted by the numeral 50. Theorganic semiconductor 33 is shown bounded on the left with thetrue-ohmic contact metal 53 of the source, and on the right by thetrue-ohmic contact metal 56 of the drain. The high barrier surround gateconductor 54 is shown positioned on the organic semiconductor 33approximately midway between the true-ohmic contact metals 53 and 56.The interconnect metals 52, 34 and 55 have been omitted for clarity.

[0054]FIG. 7 is a planar view of a three pairs of red, green and blue(RGB) emitting EL OMESFETs configured as a pixel. Green luminous ELco-polymer 74, blue luminous EL co-polymer 75, and red luminous ELco-polymer 76′ are deposited upon a transparent substrate and oxygenbarrier 79. Common source true-ohmic contact and interconnect metals aredenoted by the numeral 71. Gate electrodes for redundant green pixelelements, blue pixel elements and red pixel elements are identified as72, 76 and 78, respectfully. Elements 77 and 77′ are inter EL co-polymerisolation dielectric elements. The pixel common drain and true-ohmiccontact and interconnect is shown at 73.

[0055]FIG. 8 is a cross section of a complementary OMESFET logic device70. Such a device is suitable for controlling pixels in a video displayas will be illustrated subsequently. A logic output interconnect metalis shown at 88 contacting high barrier surrounding gates 81 and 85.Isolating dielectric 84 abuts opposing sides of the logic outputinterconnect metal 88. Element 82 is an n-type semiconductor with a highbarrier surrounding gate 81. Element 83 is a p-type semiconductor with ahigh barrier surrounding gate 84. A n-source ohmic contact metal 82′ andcooperating n-drain interconnect metal 82″ contact the n-typesemiconductor 82. Likewise, a p-drain ohmic contact metal 83′ andcooperating p-drain interconnect metal 83″ contact the p-typesemiconductor 83. A gate metal 87 contacts the high barrier surroundinggates 85 and 81, the p-type semiconductor element 83, and the n-typesemiconductor element 82. The gate interconnect metal 87 is isolatedfrom the p-drain interconnect metal 83″ and the n-drain interconnectmetal 82″ by isolating dielectric material 84.

FABRICATION BY PRINTING

[0056] The devices of the present disclosure, and more specifically acolor video display device, can be fabricated by printing elements ofthe device upon a transparent substrate in patterns and in a sequencerequired to fabricate the device.

[0057]FIG. 9 is a conceptual, planar diagram of an ink-jet printingsystem 90 filling polymer semiconductor areas in pattern and sequence toform an EL device. An ink jet 91 is supplied with appropriate materialsfor printing a device from a plurality of reservoirs 98, 98′ and 98″. Itshould be understood that additional or fewer reservoirs can beemployed. Material is fed to the ink jet printer in quantity and typeunder the control of a central processor unit (CPU) 95, which ispreprogrammed to fabricate a specific device. The ink jet 91 moves alonga path 99 back and forth across an area 97 of semiconductor materialdepositing or “writing” appropriate components until the desired patternand width is completed. Movement is controlled by the CPU 95 ispreprogrammed to fabricate a specific type of device. Printing iscarried out under a controlled atmosphere until the device isencapsulated for protection.

[0058]FIG. 9 illustrates, as an example, the ink-jet system 90fabricating a particular portion of a specific device. The exampledevice will have a potential between source 92 and drain 94, and a fieldtherebetween controlled by gate 93. The object of ink-jet printingillustrated is to provide polymer chains parallel to the field appliedto the device thereby increasing radiative emission, and reducingcross-chain carrier movement that seldom contributed to such emission.

[0059] It should be emphasized that fabrication of the devices discussedabove by material deposition is not limited to ink jet printing. Othermeans of material deposition may be used such as stamping particularelements in particular patterns. Furthermore, combinations of materialdeposition may be effectively employed. As an example, a surface oforganic semiconducting material can be fabricated by a number of means,and subsequent elements of the device can be deposited upon thesemiconductor by ink-jet printing, or by stamping, or by other suitablemethods.

FABRICATION BY WEAVING

[0060] The devices of the present disclosure, and more specifically acolor video display device, can alternately be fabricated by weaving orknitting particular inorganic and organic materials that are formed intofibers. This process is described in more detail in previously enteredreference U.S. patent application Ser. No. 09/218,233. Polymer fibers,preferably in the form of thread, are used for EL, and dielectricisolation. Metals or cermets, preferably in the form of thread, are usedfor interconnection conductive polymer. Constituent fiber dimensionsdetermine the size of the display device. Fiber width of all materialsof the display can vary from sub-micron to millimeter dimensions. Sizeof the overall display is limited by the tensile strength of interwovendielectric fibers. These fibers bear the stress of the looming of thedisplay fabric, and are allowed to stretch as long as functionalintegrity is maintained. In weaving, “woof” refers to threads woven backand forth across fixed threads of the “warp” in a loom. In the contextof the present disclosure, the length at which fiber strength fails andat which the fiber breaks determines the maximum dimension of warp andwoof of the weaving loom. Pixel density of the display is proportionalto the EL polymer fiber width, where the least display area has thehighest pixel density. For a constant pixel density as display areaincreases, the thickness of the insulating fibers are increased towithstand the increased warp and woof tensions of the loom, therebyincreasing the overall thickness of the display panel. The resultingfabric display has an overall area, or number of displays of a wovenbatch, limited only by the weaving loom's capability and the breakingpoint of the insulating fibers used. A full color flat-panel display canbe as thin, front-to-back including encapsulation, of less than one-halfinch. The display retains operational performance with mechanicalflexing.

INTEGRATED LOGIC DEVICE

[0061]FIG. 10 is a partial cross section showing an integrated logic ELdevice 100 comprising the pixel element shown in FIG. 3 and the OMESFETlogic device shown in FIG. 8. Material 184 is isolating dielectricmaterial, which surrounds many elements of the device. Contacts 132, 135and 137 are source, gate and drain contacts, respectfully, interfacingan organic semiconductor material 133. Logic output interconnect metal188 contains p-source ohmic contact metal 186 and n-drain contact metal189. The elements 183 and 182 are p-type semiconductor material andn-type semiconductor material, respectively. High barrier surround gates185 and 181 contact the elements 183 and 182, respectfully. The elements183′ and 182′ are p-drain ohmic contact metal and n-source ohmic contactmetal, respectfully, and 183″ and 182″ are p-drain and n-draininterconnect metals, respectfully. Gate interconnect metal 187 connectsthe high barrier surrounding gates 185 and 181. The entire device isencapsulated with a suitable material (not shown) to exclude oxygen.

[0062] Several complementary OMESFETs are required to accomplish anygiven logic and control functions and can be integrally fabricated inlayers above and connected to gate, source and drain terminals 34, 31and 36, respectfully, shown in FIG. 3.

[0063] While the foregoing disclosure is directed to embodiments of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof is determined bythe claims that follow.

1. An EL device comprising: (a) an EL material; (b) a interconnect metalcontacting said EL material; (c) A true-ohmic injection contactcontacting said EL material and said interconnect metal; and (d) a holeinjection barrier contact which contacts said EL material.
 2. The ELdevice of claim 1 wherein said EL device is fabricated by printing saidEL material and said true-ohmic injection contact and said interconnectmetal and said hole injection barrier contact in pattern and sequencerequired to produce cooperative elements of said EL device.
 3. The ELdevice of claim 2 wherein: (a) said EL material is first printed uponsaid hole injection barrier contact; (b) said true-ohmic injectioncontact is next printed upon said EL material; and (c) said interconnectmetal is next printed upon said EL material and said true ohmicinjection contact.
 4. The EL device of claim 1 further comprisingpolymer encapsulating material which encapsulates said EL material andsaid interconnect metal and said true-ohmic injection contact.
 5. The ELdevice of claim 1 wherein said EL material and said interconnect metaland said true-ohmic injector contact are formed into fibers and saidfibers organized in a warp and a woof of a weaving loom and are woventhereby forming a weave to fabricate said device.
 6. The EL device ofclaim 5 wherein said weave is affixed to a transparent substrate.
 7. TheEL device of claim 1 wherein said true-ohmic contact metal comprisesAl₂Li₃.
 8. The EL device of claim 1 wherein said true-ohmic contactmetal comprises CuCa₂.
 9. The EL device of claim 1 wherein said ELmaterial is organic.
 10. A method for fabricating an EL devicecomprising the steps of: (a) providing an EL material; (b) contactingsaid EL material with an interconnect metal; (c) contacting said ELmaterial and said interconnect metal with a true-ohmic injectioncontact; and (d) contacting said EL material with a hole injectionbarrier contact.
 11. The method of claim 10 wherein said EL device isfabricated by printing in pattern and in sequence required to producecooperative elements of said EL device.
 12. The method of claim 11comprising the additional steps of: (a) first depositing said ELmaterial upon said hole injection barrier contact; (b) next printingsaid true-ohmic injection contact upon said EL material; and (c) nextprinting said interconnect metal upon said EL material and said trueohmic injection contact.
 13. The method of claim 10 comprising theadditional step encapsulating said EL material and said interconnectmetal and said true-ohmic injection contact within an oxygen barrierpolymer material.
 14. The method of claim 11 comprising the additionalstep of printing with an ink jet printer.
 15. The method of claim 11comprising the additional step of printing within an oxygen freeenvironment.
 16. The method of claim 10 comprising the additional stepsof: (a) forming said EL material and said interconnect metal and saidtrue-ohmic injector contact into fibers; (b) organizing said fibers in awarp and a woof of a weaving loom; and (c) weaving said fibers with saidloom thereby forming said EL device.
 17. A OMESFET comprising: (a) asubstrate; (b) an organic semiconductor contacting said substrate; (c) afirst true ohmic contact metal contacting said semiconductor and at afirst edge of said semiconductor; (d) a second true ohmic contact metalcontacting said semiconductor at a second edge of said semiconductoropposite said first edge; and (e) a high barrier surround gatecontacting said semiconductor between said first true-ohmic contactmetal and said second true-ohmic contact metal.
 18. The OMESFET of claim17 further comprising: (a) a source interconnect metal contacting saidfirst true-ohmic contact metal; (b) a drain interconnect metalcontacting said second true-ohmic contact metal; and (c) a gateinterconnect metal contacting said semiconductor and said high barriersurround gate.
 19. The OMESFET of claim 17 wherein said high barriersurround gate is equidistant between said first true-ohmic contact metaland said second true ohmic contact metal.
 20. The OMESFET of claim 17wherein said is high barrier surround gate is spaced 3000 nm or lessfrom said first true ohmic contact metal.
 21. The OMESFET of claim 17wherein a first portion of said OMESFET is formed by depositing uponsaid substrate said semiconductor and subsequently printing said firsttrue-ohmic contact metal and said second true-ohmic contact metal andsaid high barrier surround gate in pattern and sequence required toproduce cooperative elements of said OMESFET.
 22. The OMESFET of claim21 wherein said source interconnect metal and said gate interconnectmetal and said drain interconnect metal are subsequently printed uponsaid first portion forming a second portion of said OMESFET.
 23. TheOMESFET of claim 17 wherein said semiconductor and said first true-ohmiccontact metal and said second true ohmic contact metal and said highbarrier surround gate and said source interconnect metal and said gateinterconnect metal and said drain interconnect metal are formed intofibers and said fibers are organized in a warp and a woof of a weavingloom and are woven thereby forming a weave to fabricate said OMESFET.24. The OMESFET of claim 23 wherein said weave is subsequently attachedto said substrate.
 25. The OMESFET of claim 23 wherein said first andsaid second portions are encapsulated to all components of said OMESFETfrom oxygen.
 26. A method for fabricating a OMESFET comprising: (a)providing a substrate; (b) affixing a semiconductor to said substrate;(c) affixing a first true ohmic contact metal to a first edge of saidsemiconductor; (d) affixing a second true ohmic contact to a second edgeof said semiconductor and opposite said first edge; and (e) affixing ahigh barrier surround gate to said semiconductor between said firsttrue-ohmic contact metal and said second true-ohmic contact metal. 27.The method of claim 26 further comprising the steps of: (a) contactingsaid first true-ohmic contact metal with a source interconnect metal;(b) contacting said second true-ohmic contact metal with a draininterconnect metal; and (c) contacting said semiconductor and said highbarrier surround gate with a gate interconnect metal.
 28. The method ofclaim 26 wherein said is high barrier surround gate is spaced 3000 nm orless from said first true ohmic contact metal.
 29. The method of claim26 comprising the additional step of fabricating a first portion of saidOMESFET by depositing upon said substrate said semiconductor and saidfirst true-ohmic contact metal and said second true-ohmic contact metaland said high barrier surround gate in pattern and sequence required toproduce cooperative elements of said OMESFET.
 30. The method of claim 29comprising the additional step of fabricating a second portion of saidOMESFET by printing said source interconnect metal and said gateinterconnect metal and said drain interconnect metal upon said firstportion of said OMESFET in pattern and sequence required to producecooperative elements of said OMESFET.
 31. The method of claim 26comprising the additional steps of: (a) forming said semiconductor andsaid first true-ohmic contact metal and said second true ohmic contactmetal and said high barrier surround gate and said source interconnectmetal and said gate interconnect metal and said drain interconnect metalinto fibers; (b) organizing said fibers in a warp and a woof of aweaving loom; and (c) weaving said fibers with said loom thereby forminga weave to fabricate said OMESFET.
 32. The method of claim 31 comprisingthe additional step of affixing said weave to said substrate.
 33. Themethod of claim 26 comprising the additional step of encapsulating allcomponents of said OMESFET to exclude oxygen.
 34. A video displaycomprising an EL device and integrally fabricated address and logicdevices for controlling said EL device, wherein said EL devicecomprises: (a) an EL material; (b) a interconnect metal contacting saidEL material; (c) A true-ohmic injection contact contacting said ELmaterial and said interconnect metal; and (d) a hole injection barriercontact which contacts said EL material.
 35. The display of claim 34wherein said EL device comprises at least one OMESFET comprising: (a) asubstrate; (b) an organic semiconductor contacting said substrate; (c) afirst true ohmic contact metal contacting said semiconductor and at afirst edge of said semiconductor; (d) a second true ohmic contact metalcontacting said semiconductor at a second edge of said semiconductoropposite said first edge; (e) a high barrier surround gate contactingsaid semiconductor between said first true-ohmic contact metal and saidsecond true-ohmic contact metal; (f) a source interconnect metalcontacting said first true-ohmic contact metal; (g) a drain interconnectmetal contacting said second true-ohmic contact metal; and (h) a gateinterconnect metal contacting said semiconductor and said high barriersurround gate.
 36. The display of claim 34 further comprising: (a) anoptically transparent substrate; and wherein (b) said display isfabricated by printing semiconductor elements of said display andinsulating elements of said display and metal conducting elements ofsaid display upon said substrate in pattern and sequence required toproduce cooperative elements of said display.
 37. The display of claim34 wherein: (a) semiconductor elements of said display are formed fromsemiconductor fibers, and insulating elements of said display are formedfrom insulating fibers, and metal conducting elements of said displayare formed from conducting fibers; (b) said semiconducting fibers andsaid conducting fibers and said insulating fibers are organized in awarp and a woof of a weaving loom; and (c) said semiconducting fibersand said conducting fibers and said insulating fibers are woven in saidloom to produce said video display.
 38. The display of claim 35 whereinsaid EL device comprises three pairs of red, blue and green emittingOMESFETs.
 39. A method for fabricating a video display comprising an ELdevice and integrally fabricated address and logic devices forcontrolling said EL device, the method comprising the steps of: (a)providing an organic EL material; (b) interconnecting a metal contactingsaid EL material; (c) contacting said EL material and said interconnectmetal with a true-ohmic injection contact; and (d) contacting said ELmaterial with a hole injection barrier.
 40. The method of claim 39wherein said EL device comprises at least one OMESFET comprising: (a) asubstrate; (b) an organic semiconductor contacting said substrate; (c) afirst true ohmic contact metal contacting said semiconductor and at afirst edge of said semiconductor; (d) a second true ohmic contact metalcontacting said semiconductor at a second edge of said semiconductoropposite said first edge; (e) a high barrier surround gate contactingsaid semiconductor between said first true-ohmic contact metal and saidsecond true-ohmic contact metal; (f) a source interconnect metalcontacting said first true-ohmic contact metal; (g) a drain interconnectmetal contacting said second true-ohmic contact metal; and (h) a gateinterconnect metal contacting said semiconductor and said high barriersurround gate.
 41. The method of claim 39 further comprising the stepsof: (a) providing an optically transparent substrate; (b) depositingsaid organic EL material upon said substrate; and wherein (c)fabricating said display by printing insulating elements of said displayand metal conducting elements of said display upon said substrate inpattern and sequence required to produce cooperative elements of saiddisplay.
 42. The method of claim 39 comprising the additional steps of:(a) forming semiconductor elements of said display from semiconductorfibers, and forming insulating elements of said display from insulatingfibers, and forming metal conducting elements of said display fromconducting fibers; (b) organizing said semiconducting fibers and saidconducting fibers and said insulating fibers in a warp and a woof of aweaving loom; and (c) weaving said semiconducting fibers and saidconducting fibers and said insulating fibers in said loom to producesaid video display.
 43. The method of claim 40 wherein said EL devicecomprises three pairs of red, blue and green emitting OMESFETs.
 44. TheOMESFET of claim 17 wherein said high barrier surround gate ispositioned at a distance from said first true-ohmic contact metal totune carrier balance.
 45. The method of claim 26 comprising theadditional step of tuning carrier balance by varying distance betweensaid high barrier surround gate and said first true-ohmic contact metal.